1,721,003 research outputs found
Site-specific derivatization of proteins using metal ion chelating peptides and transglutaminase
No full textHigh-yield synthesis of the terminal Re-188 N multiple bond from generator-produced [(ReO4)-Re-188](-)
No full textA novel procedure for the high-yield preparation of Re-188 radiopharmaceuticals containing a terminal ReN multiple bond is
described. This method involves the reaction of [188Re][ReO4] with N-methyl S-methyl dithiocarbazate (DTCZ), as donor of nitrido
nitrogen atoms, sodium oxalate and SnCl2 to afford a mixture of two intermediate compounds. When this mixture is reacted with the sodium
salt of a dithiocarbamate ligand (L) of the type Na[R2N-C(S)S] (R CH3, CH3CH2, CH3CH2CH2), the formation of the bis-substituted,
neutral complexes [188Re][Re(N)(L)2] is easily obtained in high yield ( 95%). The complexes [188Re][Re(N)(L)2] were characterized by
chromatographic methods, and by comparison with the corresponding complexes prepared at macroscopic level starting from a nonradioactive
rhenium precursor. Biodistribution studies were carried out in rats. Results showed that the complexes [188Re][Re(N)(L)2]
exhibited the same biological behavior of the analogous Tc-99m complexes reported previously. The easy application of the new synthetic
procedure indicates that it could be conveniently employed for preparing a large class of new Re-188 complexes having potential utilization
in nuclear medicine as therapeutic agents. © 2003 Elsevier Inc. All rights reserved
Synthesis and biological evaluation of new [Tc-99m(III)( PS)(2)(L)] mixed-ligand compounds (PS= phosphino-thiolate; L=dithiocarbamate), useful in design and development of Tc(III)radiopharmaceuticals
No full textSite-specific protein conjugation with the [185/187Re(N)(PNP)]-scaffold via Transglutaminase
No full textTechnetium-99m nitride radiopharmaceuticals
No full textFollowing the introduction of an efficient method for the preparation of technetium-99m complexes containing a terminal Tc≡N multiple bond, under conditions suitable for nuclear medicine applications, new radio-pharmaceuticals for heart and brain imaging have been discovered. These compounds belong to the class of bi-substituted, square-pyramidal nitride Tcv complexes with dithiocarbamate ligands, and are the first examples of radiopharmaceuticals of this type exhibiting inter-esting biological properties. The peculiar chemical characteristics of the Tc=N core can also be conveniently utilized for the design of radiopharmaceuticals incorporating bioactive peptides and having definite structural features. © 1997 Chapman & Hall
Uncommon Anionic Dioxorhenium(V) and Neutral Monooxorhenium(V) Mixed-Ligand Complexes Containing Heterofunctionalized Phosphine Ligands: Syntheses and Structural Characterization
No full textThe potentially bidentate hybrid ligand (o-hydroxyphenyl)diphenylphosphine, abbreviated POH, reacted via ligand-exchange with pentavalent rhenium precursors to give a series of six-coordinate mono- and dioxo complexes. Accurate control of the metal:ligand stoichiometric ratio allowed for the isolation of the mono-substituted [ReOCl3(PO)](-) (1) and [ReOCl2(PO)(PPh(3))] (2) derivatives. 1 was found to be the key intermediate for the syntheses of three more types of bis-substituted compounds: anionic dioxo [ReO2(PO)(2)][A] (A = NBu(4) (3), AsPh(4) (4)), neutral monooxo [ReOX(PO)(2)] (X = Cl (5), Br (6), I (7)), and neutral monooxo mixed-ligand [ReOX(PO)(PNH)] [PNH = (o-amidophenyl)diphenylphosphine; X = Cl (8), Br (9), I (10)] complexes. In the monosubstituted complexes, the P,O-donors of the bidentate ligand spanned an equatorial (P) and the apical position (O) trans to the Re=O linkage in a distorted octahedral arrangement. In all of the bis-substituted monooxo compounds, the second chelate ligated on the equatorial plane almost orthogonally positioned with respect to the first one, the two phosphorus donors showing a mutual cis-(P,P) orientation. Dioxo complexes retained the cis(P,P) configuration with the bidentate ligands symmetrically coordinated on the equatorial plane normal to the trans-ReO2 core. All the complexes were characterized by various physical techniques, including IR, MS, and H-1/P-31{H-1} NMR. The X-ray structure of a representative compound for each category, namely [ReOCl3(PO)][NBu(4)] (1), [ReO2(PO)(2)][AsPh(4)] (4), [ReOCl(PO)(2)] (5), and [ReOCl(PO)(PNH)] (8), were determined. Crystals of 1 were monoclinic, P2(1)/n, a = 10.840(3) Angstrom, b = 22.167(6) Angstrom, c = 15.210(4) Angstrom, beta = 95.91(2)degrees, and Z = 4; those of 4 were triclinic, P (1) over bar, a = 12.679(7) Angstrom, b = 13.082(7) Angstrom, c = 19.649(8) Angstrom, alpha = 82.64(4) Angstrom, beta = 81.16(4)degrees, gamma = 62.27(3)degrees, and Z = 2; those of 5 were orthorhombic, a = 10.225(4) Angstrom, b = 14.208(6) Angstrom, c = 21.771(9) Angstrom, P2(1)2(1)2(1), and Z = 4; and those of 8 were orthorhombic, a = 10.199(2) Angstrom, b = 14.147(4) Angstrom, c = 21.772(6) Angstrom, P2(1)2(1)2(1), and Z = 4. The four structures were solved by the Patterson method and refined by full-matrix least-squares procedures to R = 0.050, 0.063, 0.043, and 0.039 for 1, 4, 5 and 8, respectively. Both solution state (P-31{H-1} NMR) and solid state (X-ray) demonstrated a cis-(P,P) arrangement for each bis-substituted complex, with the Re atom at the center of a highly distorted octahedron. Detailed analyses of the IR spectra of this series of Re(V) compounds in the region 900-580 cm(-1) allowed us the possibility to distinguish between symmetrical and asymmetrical bis-substituted complexes
Novel TcP3X3 (X=S, O) cores in Tc(III) chemistry
No full textIn recent years we devoted most of our research efforts in developing Tc chemistry with bidentate functionalized phosphines because of their ability to act both as reducing and coordinating agents [2]. These functionalized phosphines contain a P(III) atom that can easily reduce the pertechnetate ion and stabilize the metal in lower oxidation states by means of its pi-backbonding together with the chelation of the whole ligand. In this field encouraging results have been obtained with phosphino-carboxylic derivatives of the type Ph (R=o-C6H4, C2H4, CH2 (abbreviated as P-COOH) [3] and more recently with the ligand (2-diphenylphosphino)benzeneamine (abbr. PNH2 [4]. In both cases, Tc(III) complexes of the type Tc(P-X)3 (X=COO-, NH-) have been obtained, the three mono-negative bidentate ligands being coordi nated around the metal in a meridional configuration. The above mentioned ‘reducing-coordinating’ approach has allowed the synthesis of a class of Tc(III) complexes utilizing the tris(o-thiophenyl)phosphine, a tetradentate ‘umbrella shaped’ ligand. Either octahedral or trigonal bipyramidal geometries have been observed for the resulting complexes, depending on the con centration of the ancillary isonitrile ligand [5].In this context we now report on the reaction of pertechnetate with the two bidentate functionalized phosphines, (2-diphenylphosphino)thiophenol (abbr. P-SH) and (2-diphenylphosphino)phenol (abbr. P-OH) with the aim of looking at the molecular structure of the resulting complexes and to confirm the favourable reducing and coordinating properties of such a class of ligands towards technetium. The synthesis and characterization (including X-ray structure) of the resulting Tc(III)(P-S)3 (1) and Tc(III)(P-O)3 (2) complexes are reported here
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Biodistribution in rats of bone-seeking Re188 complexes obtained under different labelling conditions
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